Simon Boulton is a senior research scientist at Cancer Research UK’s London Research Institute. His work has led to a deeper understanding of how genotoxic lesions, like those induced by a variety of cancer therapies, are sensed and repaired in cells. Moving seamlessly between model organisms he has identified and characterised many important proteins involved in the DNA damage response. He has also provided compelling evidence for the involvement of these proteins in the human DNA damage response. Among his major achievements was the discovery of the anti-recombinase, RTEL-1.